diff --git a/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.test.ts b/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.test.ts
index 8becdfe59d..fd63806fc8 100644
--- a/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.test.ts
+++ b/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.test.ts
@@ -37,5 +37,23 @@ describe('startLoopbackServer', () => {
 
     expect(response.status).toBe(204)
     expect(response.headers.get('Access-Control-Allow-Private-Network')).toBe('true')
+    expect(response.headers.get('Access-Control-Allow-Origin')).toBe('https://accounts.airi.build')
+  })
+
+  it('does not allow private-network preflight from untrusted origins', async () => {
+    const server = await startLoopbackServer()
+    servers.push(server)
+
+    const response = await fetch(`http://127.0.0.1:${server.port}/callback`, {
+      method: 'OPTIONS',
+      headers: {
+        'Access-Control-Request-Method': 'GET',
+        'Access-Control-Request-Private-Network': 'true',
+        'Origin': 'https://example.invalid',
+      },
+    })
+
+    expect(response.headers.get('Access-Control-Allow-Private-Network')).toBeNull()
+    expect(response.headers.get('Access-Control-Allow-Origin')).toBeNull()
   })
 })
diff --git a/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.ts b/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.ts
index e9497a5443..c6005a5b1a 100644
--- a/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.ts
+++ b/apps/stage-tamagotchi/src/main/services/airi/http-server/http/auth/index.ts
@@ -1,4 +1,6 @@
-import { eventHandler, getQuery, H3, handleCors } from 'h3'
+import type { CorsOptions } from 'h3'
+
+import { eventHandler, getQuery, getRequestHeader, H3, handleCors } from 'h3'
 
 import { createH3Server } from '../../server'
 
@@ -7,6 +9,8 @@ export interface LoopbackCallbackResult {
   state: string
 }
 
+const AIRI_AUTH_ORIGIN = 'https://accounts.airi.build'
+
 /**
  * Starts a temporary loopback callback server for the Electron OIDC flow.
  *
@@ -39,16 +43,18 @@ export async function startLoopbackServer(): Promise<{
 
   const app = new H3()
   const loopbackServer = createH3Server({ app, host })
-  const corsOptions = {
-    origin: '*',
+  const corsOptions: CorsOptions = {
+    origin: [AIRI_AUTH_ORIGIN],
     methods: '*',
     preflight: {
       statusCode: 204,
     },
-  } as const
+  }
+
+  function appendPrivateNetworkAccessHeaders<T extends { headers: Headers }>(event: Parameters<typeof handleCors>[0], response: T) {
+    if (getRequestHeader(event, 'origin') === AIRI_AUTH_ORIGIN)
+      response.headers.set('Access-Control-Allow-Private-Network', 'true')
 
-  function appendPrivateNetworkAccessHeaders<T extends { headers: Headers }>(response: T) {
-    response.headers.set('Access-Control-Allow-Private-Network', 'true')
     return response
   }
 
@@ -69,16 +75,16 @@ export async function startLoopbackServer(): Promise<{
   app.options('/callback', eventHandler(async (event) => {
     const corsResponse = handleCors(event, corsOptions)
     if (corsResponse !== false) {
-      return appendPrivateNetworkAccessHeaders(corsResponse)
+      return appendPrivateNetworkAccessHeaders(event, corsResponse)
     }
 
-    return appendPrivateNetworkAccessHeaders(new Response(null, { status: 204 }))
+    return new Response(null, { status: 204 })
   }))
 
   app.get('/callback', eventHandler(async (event) => {
     const corsResponse = handleCors(event, corsOptions)
     if (corsResponse !== false) {
-      return appendPrivateNetworkAccessHeaders(corsResponse)
+      return appendPrivateNetworkAccessHeaders(event, corsResponse)
     }
 
     const query = getQuery(event)